Handbook of CDMA system design, engineering, and optimization
Handbook of CDMA system design, engineering, and optimization
CDMA Systems Engineering Handbook
CDMA Systems Engineering Handbook
Multi-Carrier Digital Communications: Theory and Applications of Ofdm
Multi-Carrier Digital Communications: Theory and Applications of Ofdm
Adaptive OFDM synchronization algorithms based on discrete stochastic approximation
IEEE Transactions on Signal Processing
MIMO-OFDM wireless systems: basics, perspectives, and challenges
IEEE Wireless Communications
A robust timing and frequency synchronization for OFDM systems
IEEE Transactions on Wireless Communications
IEEE 802.20: Mobile Broadband Wireless Access for the Twenty-First Century
IEEE Communications Magazine
New schemes of integer frequency offset estimation using pilots for DVB-T systems
Proceedings of the 6th International Wireless Communications and Mobile Computing Conference
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Orthogonal frequency division multiplexing (OFDM) has become a promising physical layer modulation technology for beyond 3G or 4G wireless communications due to effective inter-symbol interference mitigation for high speed data transmission. However, the timing of the OFDM symbol, i.e., the placement of the DFT collection window in a multi-path time dispersive channel remains an important and challenging issue in OFDM receiver design. An erroneous timing decision creates inter-symbol interference (ISI), inter-carrier interference (ICI), channel attenuation, and channel estimation error, which leads to a penalty on the collected OFDM symbol signal to noise ratio (SNR) resulting in an irreducible error floor. In this paper we quantify such effects and derive an optimal OFDM symbol timing solution in the sense of maximizing the signal to interference ratio (SIR) of the collected OFDM symbol. A practical timing algorithm, referred to as the equilibrium algorithm, is then developed to approximate the optimal timing decision. Compared with existing schemes in the literature, the proposed approach does not rely on explicit detection of individual channel paths or the delay spread boundary and therefore greatly reduces timing complexity. The equilibrium algorithm performs nearly as well as the optimal solution over a variety of channel delay spreads, is simple to implement, and is robust to channel estimation errors.